Conventional brake systems having control units and electronic components, use structural measures and/or cooling elements to cool the electronic components. In addition, the components in automotive engineering can usually withstand loads up to certain temperatures for a limited period of time. The required load profiles for engine space conditions are met with component specifications for temperatures up to 140° C., for example. At very high temperatures (e.g., more than 140° C.), the electronic components are thermally overloaded and destroyed.
In addition, there is a variety of conventional control units, available in particular for controlling a brake system of a motor vehicle. Many variations of such brake systems are known. Such a brake system has at least one brake circuit in which there is at least one means for conveying the pressure medium, e.g., a pump, which is also known as a return pump, in hydraulic brake systems. In addition, optionally at least one more means, for conveying the pressure medium, in particular a self-priming supercharge pump may be provided, which is connected to a supply tank for the pressure medium by a suction line. The intake and outflow of pressure medium in the brake circuit and the intake and outflow of pressure medium in the respective wheel brake cylinder are controlled by cutoff elements, in particular valves, for intake and/or outflow and/or through-flow of pressure medium.
This arrangement is also used in principle in an electrohydraulic brake system, as described in German Patent Application No. 195 48 248 , in which the pressure medium is supplied to valves and comes from valves through a pump with an intermediate accumulator. The pressure medium is then introduced into the wheel brake cylinders or drained out of them, thus regulating the brake pressure, by the opening and closing of the inlet and outlet valves according to the driver's braking request and/or the control signals of a logical switching system such as an anti-lock brake system (ABS), a traction control (ASR), a driving dynamics control (FDR, ESP) or an adaptive cruise control (ACC). With an electrohydraulic brake system, the brake pressure and/or the system pressure is controlled electrically by the control for the cutoff devices for the inflow and/or outflow and/or through-flow of the pressure medium and/or by the means conveying the pressure medium. Likewise, this is implemented with a hydraulic brake system with hydraulic power-assisted braking and a pneumatic brake system.
Complete brake systems with such control units are described in, for example, Bosch “Automotive Handbook,” 22nd edition, pages 624–677.
With the conventional brake systems, different methods can be implemented for controlling the brake system.
German Patent Application No. 195 48 248 describes a method and device for controlling a pump in an electrohydraulic brake system, in which the pump can be controlled with a mark-to-space ratio, i.e., a clock ratio, which can be predetermined according to demand. For example, control of the brake pressure in certain situations and the associated driving of, for example, valves or pumps required for this are also known with traction control (ASR), an anti-lock brake system (ABS), driving dynamics control (FDR, ESP), an adaptive cruise control (ACC) or hydraulic power-assisted braking (HBV).
Finally, German Patent Application No. 196 15 449 describes a method and a device for controlling the brake system of a vehicle so that the driver's braking request is formed from a pressure of the brake system which can be influenced by the driver, and the brake system is controlled as a function of the driver's braking request. Another conventional method of detecting the driver's braking request is by the analysis of brake pedal movement.